The invention is concerned with detergent formulations comprising detergents and additives to improve properties of the detergents. In particular the inventive additives substitute for known so-called "softening", "whitening" and "anti-cling" (anti-static) agents.
Substantial development work takes place continuously to improve the performance of cleaners, particularly home laundry detergents. This is apparent from the information which can be gleaned from patents and the scientific and trade literature. Much attention is directed towards better soil removal; however simplifying the washing procedure is also considered important to the consumer. If cleaning, softening, and the reduction or elimination of static charges can be accomplished simultaneously with a single detergent composition (eliminating the addition of special chemicals to the rinse water), time and effort and expense will be saved in home laundry chores to the delight of the homemakers.
It is therefore an object of the invention to provide a simple detergent formulation that results in improved cleaning, while softening the fabrics being laundered and providing anticling or antistatic action.
The chemicals now required to accomplish these objects are numerous, and the manufacture of the finished laundry products often is tedious and difficult. Formulations have been described with as many as at least 17 different components, Embodiment IV of the European Patent Application No. 0,111,976, page 34 (1984) or at least 18 ingredients in Example IV of U.S. Pat. No. 4,515,705 (1984), not including minor additives and water. For many years, the art has taught that for good performance compounds with hydrocarbon chains of 12 carbon atoms and over, preferably of 16-18 carbon atoms must be used for laundry detergent additives for softening the laundry. This is evident from the scientific literature and also from the fact that the examples given in the patent literature always list carbon chains with 12 to 18 carbon atoms, predominantly 14 to 18 carbon atoms.
One of the most effective prior art softeners is dimethyl-dialkylammonium chloride where the dialkyls are either tallow or stearyl radicals: ##STR1## containing a total chain length of C.sub.36 interrupted, however, by the quaternary nitrogen which may decrease the softening effect to some extent.
Furthermore, technical books which deal directly with textile softeners direct persons skilled in the art to long chain compounds. Most to the point is perhaps the statement in "Handbuch der Textilhilfsmittel", Verlag Chemie 1977 which, in the last paragraph of page 685 dealing with Chemical Constitution of the Softeners states that in practice the compounds based on fat-oil-, and silicon derivatives are predominantly used. As a rule these substances have one common characteristic: they have all a long-chain fat residue (according to rule they are products with a carbon number of between 16 and 18), which cause the softening action.
In the text "An Introduction to Textile Finishing" by English textile chemist J. T. Marsh (1966 edition) there is a general overview of "Softening" in Chapter X. Specifically at page 260 last paragraph Marsh states that although many hundreds of preparations are available for softening textile materials, it is noteworthy that they are all based on long-chain fatty compounds in one guise or another. Long chain fatty compounds are generally those which contain 12 and more carbons in the chain. Soaps, oils, fats and waxes have usually 16 to 18 and more carbon atoms in their chain. Coconut is the primary exception; however this oil has fatty acids with the fractions with longer chains containing 12 and more carbon atoms generally amounting to over 80% of the total. Thus the presence of C.sub.4 to C.sub.10 chains if mentioned in any prior art compilations, refers to their presence in coconut oil, where they play a very minor role.
On page 264 Marsh further points out the use of tallow for many years has shown the importance of a fatty chain of 16 to 18 carbon atoms.
Finally, at page 271 under "Cation-active Softeners" (to which the imidazolines of this invention belong) it is taught that modern cation-active softeners appear to originate from attempts made in 1933 to improve the fastness of acid and direct dyestuffs by forming a lake; the short-chain cation-active bodies were relatively ineffective but the long-chain compounds were better and also imparted a highly desirable softness of handle for which they are now mainly used.